Generator set integrated gearbox

ABSTRACT

A generator set comprises an engine including a crankshaft rotatable in a first direction about a longitudinal axis of the generator set, and a generator including a generator shaft. A gearbox is positioned between the engine and the generator, all mounted on a chassis. The gearbox couples the crankshaft to the generator shaft. The gearbox includes a gearbox housing having a first end and a second end. The first end is coupled to an engine first end and the second end is coupled to a generator first end. The gearbox also includes a gear set including a plurality of gears, a first gear shaft coupled to a crank shaft first end, and a second gear shaft coupled to a generator shaft first end. The crankshaft and at least a portion of the plurality of gears, and the generator shaft are axially aligned along the longitudinal axis of the generator set.

TECHNICAL FIELD

The present disclosure relates generally to generators sets (gensets)for energy generation.

BACKGROUND

Gensets are used for various power generation applications which caninclude industrial or consumer power generation. Gensets generallyinclude an engine, for example an internal combustion (IC) enginerunning on gasoline, diesel, natural gas, dual-fuel, biodiesel or anyother fuel, and a generator for converting the mechanical work performedby the engine into electrical energy such as an alternator. The engineis coupled to the generator using a gearbox which can include gears toadjust the speed, power and/or torque produced by the engine andtransferred to the generator.

SUMMARY

In some embodiments, a generator set includes an engine including acrankshaft rotatable in a first direction about a longitudinal axis ofthe genset, and a generator including a generator shaft. A gearbox ispositioned between the engine and the generator. The gearbox couples thecrankshaft to the generator shaft. The gearbox includes a gearboxhousing having a first end and a second end. The first end is structuredto couple to an engine first end of the engine and the second end isstructured to couple to a generator first end of the generator. A firstflange rigidly couples the first end of the gearbox housing to theengine first end, and a second flange rigidly couples the second end ofthe gearbox housing to the generator first end. The gearbox alsoincludes a gear set including a plurality of gears, a first gear shaftcoupled to a crank shaft first end, and a second gear shaft coupled to agenerator shaft first end. The generator set also includes a skid frame.Each of the engine, the gearbox and the generator are positioned on andcoupled to the skid frame. The crankshaft and at least a portion of theplurality of gears, and the generator shaft are axially aligned alongthe longitudinal axis of the generator set. Furthermore, the gearboxinterfaces with the engine and the generator to form a rigid torque tubestructure.

In some embodiments, a gearbox for coupling a crankshaft of an engine toa generator shaft of a generator includes a gearbox housing having afirst end and a second end. The first end is structured to couple to anengine first end and the second end is structured to couple to agenerator first end. The gearbox housing is structured to be positionedon and rigidly coupled to a skid frame. The gearbox also includes a gearset including a plurality of gears, a first gear shaft and a second gearshaft. The first gear shaft is structured to couple to a crank shaftfirst end. Furthermore, a second gear shaft is structured to couple to agenerator shaft first end such that the crankshaft, at least a portionof the plurality of gears, and the generator shaft are axially alignedwhen the gearbox is coupled to the engine and the generator.

In some embodiments, a method of coupling a crankshaft of an engine to agenerator shaft of a generator includes providing a gear box. Thegearbox includes a gearbox housing having a first end and a second end.The gearbox also includes a gear set including a plurality of gears, afirst gear shaft and a second gear shaft. The first end of the gearboxhousing is coupled to an engine first end. The first gear shaft iscoupled to a crankshaft first end such that at least a portion of theplurality of gears are axially aligned with the crankshaft. The secondend of the gearbox housing is coupled to an engine second end. Thesecond gear shaft is coupled to a generator shaft. Each of the engine,the gearbox and the generator are positioned on and rigidly coupled to askid frame such that the crankshaft, the generator shaft, and at least aportion of the plurality of gears are axially aligned. Furthermore, theengine, the gearbox and the generator form a rigid torque tube.

In some embodiments, a generator set comprises an engine including acrankshaft rotatable in a first direction about a longitudinal axis ofthe generator set, and a generator including a generator shaft. Agearbox is positioned between the engine and the generator and couplesthe crankshaft to the generator shaft. The gear box includes a gearboxhousing having a first end and a second end. A first flange rigidlycouples the first end of the gearbox housing to the engine first end,and a second flange rigidly couples the second end of the gearboxhousing to the generator first end. The gearbox also includes a gear setincluding a plurality of gears. A first gear shaft is coupled to acrankshaft first end of the crankshaft, and a second gear shaft iscoupled to a generator shaft first end of the generator shaft. Thegenerator set also includes a skid frame. Each of the engine and thegenerator are positioned on and rigidly coupled to the skid frame.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several implementations in accordance withthe disclosure and are therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings.

FIG. 1 is a schematic illustration of a generator set including anengine, a generator and a gearbox positioned therebetween.

FIG. 2 is a perspective view of another embodiment of a generator setwhich includes an engine, a generator and a gearbox positionedtherebetween operatively coupling the engine to the generator.

FIGS. 3A-C are finite element analysis (FEA) model of various mode ofvibrations of the genset of FIG. 2.

FIG. 4 is a perspective view of a portion of a genset assembly showingan adaptor rigidly coupling a second end of a gearbox to a generatorfirst end.

FIG. 5 is another perspective view of the genset assembly of FIG. 4showing a first piece of the adaptor uncoupled from a second piece ofthe adaptor.

FIG. 6 is an exploded view of the adaptor of FIG. 4.

FIG. 7 is a perspective view of a flexible coupling assembly couplingthe gearbox of FIG. 9 to a generator first end and a generator shaft ofthe generator.

FIG. 8 is an exploded view of the flexible coupling assembly of FIG. 7.

FIG. 9 is a side cross-section view of the flexible coupling assembly ofFIG. 7.

FIG. 10 is a side cross-section view of a gearbox showing an elasticcoupling for coupling a first gear shaft and/or a second gear shaft to acrankshaft or a generator shaft, respectively.

FIG. 11 is a perspective view of the elastic coupling of FIG. 10.

FIGS. 12 and 13 are perspective views of a chassis for mounting andrigidly securing the engine, the gearbox and the generator thereon.

FIG. 14 is a method of operatively coupling an engine to a generator viaa gearbox coupled to the engine and generator and structured to axiallyalign the crankshaft of the engine and the generator shaft.

FIG. 15 is a schematic illustration of a generator set including anengine, a generator, a chassis and a gearbox; FIG. 15A shows a sidecross-section of a chassis included in the generator set of FIG. 15having a neutral axis if the gearbox is not rigidly attached to theengine and generator, and FIG. 15B shows the side cross-section of thechassis and gear box with the engine, the generator mounted thereon withthe gear box coupled to the engine and the generator causing a shift inthe neutral axis.

FIG. 16 is a schematic illustration of a generator set including anengine, a generator and a gearbox rigidly coupled to the engine, thegenerator and a skid frame.

FIG. 17 is a schematic illustration of a generator set including anengine, generator and a gearbox operatively coupling a crankshaft of theengine to a generator shaft of the generator such that the crankshaftand the generator shaft are vertically offset.

FIG. 18 is a perspective view of a generator set including an engine, agenerator vertically offset from the engine, and a gearbox operativelycoupling a crankshaft of the engine to a generator shaft of thegenerator.

Reference is made to the accompanying drawings throughout the followingdetailed description. In the drawings, similar symbols typicallyidentify similar components, unless context dictates otherwise. Theillustrative implementations described in the detailed description,drawings, and claims are not meant to be limiting. Other implementationsmay be utilized, and other changes may be made, without departing fromthe spirit or scope of the subject matter presented here. It will bereadily understood that the aspects of the present disclosure, asgenerally described herein, and illustrated in the figures, can bearranged, substituted, combined, and designed in a wide variety ofdifferent configurations, all of which are explicitly contemplated andmade part of this disclosure.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Generally, gearboxes used for operatively coupling the engine to thegenerator (e.g., an engine crankshaft to a generator shaft) arefreestanding or structurally independent gearboxes which include gearswhich are operatively coupled to each of the crankshaft and thegenerator shaft, in particular on high horsepower large displacementgensets (e.g., greater than 500 kW\). The gearbox is generallystructured such that an axis of the crankshaft and the generator shaftare offset from each other. Furthermore, the gears are operative tocause the generator shaft to rotate in an opposite direction relative tothe crankshaft. In such assemblies, the reaction torque stress ofon-going torque output or sudden torque/power output step functions(rising or falling) produced by the crankshaft are generally absorbed bythe gearbox and translated to a mount or chassis on which the gearbox ismounted. This focused stress requires enhanced mounting arrangements forthe gearbox and an over-engineered skid frame or chassis to take theentire reactive torque stress of the genset to absorb the torque stressthe engine is applying to drive the generator as well as the mountingstress from the gearbox on the relatively planar skid frame and avoidframe/mount cracking, particularly with large high horsepower gensets.This raises the weight, cost, and physical dimensions of the chassis.Moreover, the misalignment of the crankshaft and the generator shaftalso increase the physical dimensions of the genset.

In some instances, the gearbox included in large gensets, for examplegensets having a power rating of greater than 500 kW, are open coupledwith the engine and/or generator of the genset (e.g., such that thegearbox is not bolted or otherwise rigidly fixed to the engine and/orgenerator). A casing of the gearbox is mounted on a chassis or frame onwhich the engine and/or generator of the genset are positioned and thetorque produced by the crankshaft and the gearbox are transferredthrough a casing of the gearbox to the chassis or frame. This increasesthe load and mechanical strength requirements of the chassis or framesuch that the chassis is often structured to have sufficient mechanicalstrength and rigidity for supporting the weight of the gearbox as wellas the torque produce by the gearbox.

Embodiments described herein relate generally to systems and methods forcoupling a crankshaft of an engine with a generator shaft of a generatorusing a gear box. Particularly, various embodiments described hereinrelate to a gearbox which includes a housing physically coupled to theengine and the generator and is structured to couple the crankshaft ofthe engine to the generator shaft of the generator so that thecrankshaft, the generator shaft and at least a portion of a plurality ofgears in the gear box are axially aligned, which may be considered as aclose coupled system.

Embodiments of the genset integrated gearbox described herein mayprovide several benefits including, for example: (1) structurallyintegrating the gearbox, engine, generator, and optionally, the skidframe to spread a torque load generated by the crankshaft through agearbox housing of the gearbox by physically coupling the gearboxhousing to the engine and generator, and mounts of the engine and thegenerator to a chassis or frame on which the engine, the gearbox and thegenerator are mounted; (2) concentrating structural strength at theinterface between the engine and the generator where it is required andreducing the torque stress on the mounts, frame or other portions of thechassis; (3) reducing the overall size of the genset allowing for a morecompact system, thereby reducing required installation footprint; (4) byspreading the torque load over the engine, gearbox and generator,allowing reduction of the size and structural requirements of thechassis due to reduced torque load, use of less expensive chassismaterials, and lower strength requirements; (5) allowing lowering of thechassis profile, allowing the genset to have lower height, less weightand smaller space requirements, thereby fitting more readily intoenclosures and tight customer spaces and reducing handling and shippingcosts; (6) increasing resonant frequencies to higher modes which arestructurally less problematic by stiffening the genset with anintegrated gearbox; (7) allowing rotation of the crankshaft andgenerator shaft in the same direction, reducing overall stress on thechassis and the interface between the engine and the generator; (8)allowing better access to regions below the gearbox for maintenanceoperations by reducing the chassis structure; and/or (9) providingauxiliary power gears (also referred to herein as “idler shaft gears”)for recovering waste energy (e.g., via exhaust energy recovery turbinesor organic Rankine cycle heat recovery) that is rerouted to main gearsof the gearbox.

As used herein, the term “torque tube” refers to a rigid overallstructure formed via rigid structural coupling or otherwise integrationof a gearbox, an engine and a generator included in a genset assembly toeach other so that the overall structure reacts to a torque in the samedirection.

FIG. 1 shows a schematic illustration of a genset 100 according to anembodiment. The genset 100 includes an engine 110, a gearbox 120, agenerator 140 and skid frame or chassis 150. The genset 100 can be usedfor industrial and/or consumer electrical power generation. The genset100 may be a back-up power source in the event of a loss of electricalgrid power. In one implementation, the genset 100 may be provided tosubsidize grid electricity (parallel to the grid) or as the primarypower source when grid electricity is not being used or when gridelectricity fails. In other implementations, the genset 100 may beprovided as a secondary source of power for homes or businesses. In yetanother implementation, the genset 100 may be the primary source ofpower where grid power is not readily available, such as remotelocations or construction sites. The genset 100 can also be used as aprimary power source for marine vessels, railway engines, constructionequipment, or any other application where mechanical and/or electricalpower is desired.

In some embodiments, the engine 110, the gearbox 120 and the generator140, coupled to each other and mounted on the chassis or skid frame 150may be positioned within an enclosure 102 (e.g., a container or a brickand mortar facility). In various embodiments, the enclosure 102 caninclude a shipping container (e.g., the International Organization forStandardization (ISO) 6346 standard container).

The engine 110 can include an IC engine (e.g., a diesel engine) whichconverts fuel (e.g., diesel, gasoline, ethanol, natural gas, biodiesel,etc.) into mechanical energy. In some embodiments, the engine 110includes a large engine have a volumetric capacity of equal to orgreater than 95 liters. The engine 110 can include a plurality of pistonand cylinders pairs (not shown) for combusting the fuel to producemechanical energy. The engine 110 also includes a crankshaft 112 coupledto the plurality of pistons and structured to rotate in response toreciprocating motion of the pistons. The crankshaft 112 is axiallyaligned along a longitudinal axis A_(L) of the genset 110 and isrotatable in a first direction along the longitudinal axis A_(L) asshown by the arrow A in FIG. 1.

The engine 110 is operably coupled to the generator 140, via the gearbox120 as described herein. The generator 140 may include an alternator,for example a wound rotor or permanent magnet alternator configured toconvert a rotational mechanical power produced by the engine 110 intoelectrical energy. The generator 140 is configured to produce anelectrical output. The electrical output can include a voltage and/or acurrent, and is proportional to the speed or torque provided by thecrankshaft 112 to the generator 140. The generator 140 includes agenerator shaft 144 operatively coupled to the crankshaft 112 via thegearbox 120, as described herein.

The gearbox 120 is positioned between the engine 110 and the generator140 and operatively couples crankshaft 112 to the generator shaft 114,thereby allowing mechanical energy to be transmitted from the crankshaft112 to the generator shaft 144 for producing electrical energy. Thegearbox 120 includes a gearbox housing 122 and a gear set 130 positionedwithin an internal volume defined by the gearbox housing 122. Thegearbox housing 122 includes a first end 121 coupled to an engine firstend 111 of the engine 110. Furthermore, the gearbox housing 122 includesa second end 125 coupled to a generator first end 145 of the generator140. The structural coupling of the engine 110, the gearbox housing 122and the generator 140 provides enhanced mechanical stiffness andstrength to the genset 100. Because of the structural coupling, theengine 110, the gearbox housing 122 and the generator 140 essentiallyform an integrated torque bearing structure or a “torque tube” fortransmission of torque load between the coupled elements of the engine110, the gearbox 120, and the generator 140.

Each of the engine 110, the gearbox 120 and the generator 140 arepositioned on the skid frame, base frame or chassis 150. The chassis 150may function to position the engine 110, the gearbox 120, and thegenerator 140 so that they may be rigidly coupled without built inassembly stresses. The increased strength of the engine 110, the gearbox120 and the generator 140 coupling reduce torque and load bearingdemands of the chassis 150, thereby allows reduction in demand onchassis 150 so as to allow strength and material of the chassis 150 tobe optimized so as to reduce cost. Furthermore, rigid coupling of eachof the engine 110, the gearbox 120 and the generator 140 to the chassis150 and to each other further adds to the structural strength of thetorque tube structure formed thereby.

As shown in FIG. 1, the chassis 150 includes a planar frame (e.g., askid frame) on which the engine 110, the gearbox 120 and the generator140 are mounted. In various embodiments, the chassis 150 can have anyother shape, size or configuration. For example, the chassis 150 caninclude a side truss or tubular space frame positioned around and/orcoupled to the engine 110, the gearbox 120 and the generator 140 tofurther increase torque transmission capacity, alter resonance frequencyresponse, and increase stiffness of the resulting structure.Alternatively, the truss or space frame can be integrated inside anenclosure structured to house the genset 100, which can lower theoverall height of the genset 100, reduce material usage and increasestiffness.

The gearbox housing 122 can be formed from any suitable material forabsorbing torque produced by the engine 110 because of the rotation ofthe crankshaft 112, for example, cast iron, ductile iron, gray iron,alloys, any other suitable material or a combination thereof. Forexample, a first portion of the gearbox housing 122 proximate to thefirst end 121 and a second portion of the gearbox housing 122 proximateto second end 125 can be formed from gray iron to provide high strengthand resistance to stress at the interface between the engine 110 and thegearbox housing 122, and the interface between the gearbox housing 122and the generator 144, respectively. Moreover, a third portion of thegearbox housing 122 between the first portion and the second portion canbe formed from ductile iron which has higher elasticity, therebyproviding higher vibration damping and elastic deformation toaccommodate torque generated by the crankshaft 112.

The gearbox housing 122 may be coupled to the chassis 150 via aninterface. For example, the gearbox housing 122 can include feetincluding apertures for coupling the gearbox housing 122 to the chassis150 via fasteners (e.g., screws, bolts, rivets, pins, etc.). In someembodiments, shock absorbers such as springs, rubber pads, foam pads,hydraulic dampers or any other shock absorbing assembly are positionedbetween the gearbox housing 122 and the chassis 150, thereby reducingthe vibrations or shock transferred from the gearbox 120 to the chassis150. In some embodiments, gearbox housing 122 may be mounted on thechassis 150 via “vibracons” or any other adjustable mount.

The gear set 130 is positioned within the internal volume defined by thegearbox housing 122 and includes a plurality of gears for providing amechanical linkage between the crankshaft 112 and the generator shaft144 that can provide a desired turn ratio, torque ratio, or reorientdirection of rotation from the crankshaft 112 to the generator shaft144. Expanding further, the gear set 130 includes a first gear shaft 132coupled to a crankshaft first end of the crankshaft 112, and a secondgear shaft 134 coupled to a generator shaft first end of the generatorshaft 144.

The first gear shaft 132 is coupled to the crankshaft first end via afirst coupling 133. In various embodiments, the first coupling 133 caninclude a flex plate. A flywheel (not shown) can be coupled to thecrankshaft first end and coupled to the flex plate. In such embodiments,the gearbox housing 122 can be structured such that the flywheel ispositioned within the internal volume defined by the gearbox housing122, for example an internal volume defined by the first portion of thegearbox housing 122. The second gear shaft 132 and the generator shaft144 are coupled together via a second coupling 135 which can include,but is not limited to, a rubber coupling, a spring coupling, or aviscous coupling. The rubber coupling, spring coupling, or the viscouscoupling can be structured to maintain operative coupling of the secondgear shaft 134 to the generator shaft 144 under varying torqueconditions by allowing slight misalignment between the second gear shaft134 and the generator shaft 144.

The gear set 130 is structured so that the crankshaft 112, at least aportion of the plurality of gears included in gear set 130 and thegenerator shaft 144 are axially aligned along the longitudinal axisA_(L) of the generator set 100. In various embodiments, the gear set 130is structured to cause the generator shaft 144 to rotate in the samedirection as the crankshaft 112, i.e., the first direction shown by thearrow A. The structure coupling the gearbox housing 122 to each of theengine 110 and the generator 140 and/or the rotation of the crankshaft112 and the generator shaft 144 in the same direction can cause each ofthe engine 110, the gearbox 120 and the generator 140 to react, or“torque react,” in the same direction in response to the torquegenerated by the crankshaft 112. In other embodiments, the gearbox 120can cause the engine 110 and generator 140 to rotate in oppositedirections to cancel vibration inputs and lessening spring mounting ofgenset while absorbing torque reaction in the increased stiffness of theskid frame 150, engine 110, gearbox 120, and generator 140.

Any suitable arrangement or combination of gears can be used in the gearset 130 which can include, for example spur gears, helical gears,herringbone gears, worm and wheel gears, bevel gears, etc. In variousembodiments, the plurality of gears included in the gear set 130 includea first pair of gears (not shown) operably coupled to crankshaft 112 andthe generator shaft 144 via the first gear shaft 132 and the second gearshaft 134. The first pair of gears are axially aligned along thelongitudinal axis A_(L) of the genset 100 and can be structured to causethe generator shaft 144 to rotate in the first direction as describedbefore.

Furthermore, the gear set 130 can also include a second pair of gears(not shown) operably coupled to the first pair of gears. The second pairof gears are axially offset from the longitudinal axis A_(L) of thegenset 100 in a vertical or horizontal direction. In some embodiments,the second pair of gears can be configured to adjust (i.e., increase ordecrease) a speed or the torque provided by the crankshaft 112 to thegenerator shaft 144. In some embodiments, the gear set 130 can alsoinclude an auxiliary power gear (not shown) operably coupled to at leastone of the plurality of gears. The auxiliary power gear is structured tobe coupled to an auxiliary power source or renewable power source, forexample an exhaust gas recirculation (EGR) system turbine, or an organicRankine cycle (ORC) turbine to provide auxiliary power to the gear set130. This can increase engine 110 efficiency or otherwise supplement thetorque provided to the generator shaft 144 to increase electricaloutput. In various embodiments, the auxiliary power gear can also beused to drive a main oil pump fluidly coupled to the gearbox 120 tosupply a lubricant therein to lubricate the gear set 130, filter thelubricant and/or exchange lubricant with an oil sump. An auxiliary oilpump (e.g., an electrical oil pump) can also be provided to provide apre-lubrication to the gear set 130 before beginning of an operationalrun and/or provide backup oil supply in the event that the main oil pumpfails.

In some embodiments, the gear set 130 also includes an engine turningmechanism (not shown) configured to turn the engine 110 over, forexample for maintenance or repair. For example, the engine turningmechanism may include an electric powered gear and is selectivelycoupleable to the gear set 130. Providing power to the electric poweredgear may cause the gear to couple to the gear set 130 and rotate,thereby causing the gear set 130 to rotate. This in turn rotates thecrankshaft 112 so as to move a plurality of pistons positioned in aplurality of cylinders of the engine 110 to displace therewithin.

As described herein, the engine 110, the gearbox 120 and the generator140 can be coupled together and mounted as a structurally integral uniton the chassis 150. The structural coupling allows spreading of thetorque load generated by the crankshaft 112 through a gearbox housing122 to the chassis 150, thereby reducing the load requirements of thechassis 150. Physically coupling the gearbox housing 122 to the engine110 and the generator 140 increases the structural strength at theinterface between the engine 110 and the generator 140 and reducing thetorque stress on the chassis 150. This may allow for optimized design ofthe chassis 150 for reduced torque load so as to allow strength andmaterial of the chassis 150 to be optimized and reduce cost.

Axial aligning of the crankshaft 112, the gearbox 120 and the generatorshaft 144 as well as structural coupling of the gearbox 120 to theengine 110 and the generator 140 also reduces the overall length of thegenset 100 and lowers the chassis profile, thereby allowing the genset100 to have a lower height, less weight and smaller space requirements.This enables the genset 100 to fit more readily into enclosures andtight customer spaces, and reduces handling and shipping costs.Furthermore, the gearbox 120 can lower the number of resonant vibrationfrequencies, and move the remaining resonant frequencies to higher modeswhich are structurally less problematic.

As described before, the gear set 130 can be structured to allowrotation of the crankshaft 112 and generator shaft 144 in the samedirection which causes the engine 110, the gearbox 120, and thegenerator 140 to react in the same direction in response to the torqueproduced by the crankshaft 112. This reduces overall stress on thechassis 150 and the interface between the engine 110 and the generator140. Reducing of the load and structural strength requirements of thechassis 150 allows less structural members (e.g., cross bars, beams,etc.) to be used in the chassis 150. This can enable better access toregions below the gearbox 120 for maintenance operations and/orpositioning of at least one of a gearbox oil sump for the gearbox 120,filters or other support features or assemblies, as well as allowingimproved serviceability. Further, providing auxiliary power gears forrecovering waste energy (e.g., via exhaust energy recovery turbines ororganic Rankine cycle heat recovery) which is rerouted to main gears ofthe gearbox 120 increases the efficiency of the genset 110.

FIG. 2 is a perspective view of another embodiment of a genset 200. Thegenset 200 includes an engine 210, a gearbox 220 and a generator 240mounted on a chassis 250. The genset 200 can be used for industrialand/or consumer electrical power generation, or any other application asdescribed before with respect to the genset 100.

The engine 210 includes an IC engine (e.g., a diesel engine) whichconverts fuel (e.g., diesel, gasoline, ethanol, natural gas, biodiesel,etc.) into mechanical energy. In some embodiments, the engine 210includes a large engine have a volumetric capacity of equal to orgreater than 95 liters. The engine 210 can include a plurality of pistonand cylinders pairs 214 for combusting the fuel to produce mechanicalenergy. The engine 210 also includes a crankshaft coupled to theplurality of pistons and structured to rotate in response toreciprocating motion of the pistons. The crankshaft is axially alignedalong a longitudinal axis A_(L) of the genset 210 and is rotatable in afirst direction along the longitudinal axis A_(L) (e.g., a clockwise oranti-clockwise direction). The engine 210 includes auxiliary componentscoupled thereto which can include, for example an air intake, filters,an intercooler, an exhaust gas recirculation system, an aftertreatmentsystem or any other systems to increase the efficiency of the engine 210and reduce exhaust emissions.

The engine 210 is coupled to the generator 240 via the gearbox 220, asdescribed herein. The generator 240 may include an alternator, forexample a wound rotor or permanent magnet alternator configured toconvert a rotational mechanical power produced by the engine 210 intoelectrical energy. The generator 240 is configured to produce anelectrical output. The electrical output can include a voltage and/or acurrent, and is proportional to the speed or torque provided by thecrankshaft to the generator 240. The generator 240 includes a generatorshaft coupled to the crankshaft via the gearbox 220, as describedherein.

The gearbox 220 is positioned between the engine 210 and the generator220 and couples crankshaft to the generator shaft 214, thereby allowingmechanical energy to be transmitted from the crankshaft to the generatorshaft for producing electrical energy. The gearbox 220 includes agearbox housing 222 and a gear set positioned within an internal volumedefined by the gearbox housing 222.

The gearbox housing 222 includes a first end 221 coupled to an enginefirst end 211 of the engine 210. Furthermore, the gearbox housing 222includes a second end 225 coupled to a generator first end 245 of thegenerator 240. Coupling can be performed via fasteners (e.g., screws,bolts, rivets, etc.) welding, fusion bonding, adhesives or any othersuitable coupling mechanism. The structural coupling of the engine 210,the gearbox housing 222, and the generator 240 provides enhancedmechanical stiffness and strength to the genset 200, as described beforewith respect to the genset 100. Each of the engine 210, the gearbox 220,and the generator 240 are positioned on the chassis 250. The increasedstrength of the engine 210, the gearbox 220, and the generator 240assembly due to structural coupling therebetween reduces torque and loadbearing demands of the chassis 250, thereby allowing reduction inchassis 250 strength, material and cost.

As shown in FIG. 2, the chassis 250 includes a planar frame (e.g., askid frame) on which the engine 210, the gearbox 220 and the generator240 are mounted. In other embodiments, the chassis 250 can have anyother shape, size or configuration. For example, the chassis 250 caninclude a side truss or tubular space frame positioned around the engine210, the gearbox 220 and the generator 240 or integrated inside anenclosure structured to house the genset 200. This can lower the overallheight of the genset 200, reduce material usage and increase stiffness,as described herein with respect to genset 200.

The gearbox housing 222 can be formed from any suitable material forabsorbing torque produced by the engine 210 because of the rotation of acrankshaft of the engine 210, for example, cast iron, ductile iron, grayiron, alloys, any other suitable material or a combination thereof. Forexample, in some embodiments, a first portion of the gearbox housing 220proximate to the first end 221 and a second portion of the gearboxhousing 222 proximate to second end 225 can be formed from gray iron toprovide high strength and resistance to stress at the interface betweenthe engine 220 and the gearbox housing 222, and the interface betweenthe gearbox housing 222 and the generator 240, respectively. Moreover, athird portion of the gearbox housing 222 between the first portion andthe second portion can be formed from ductile iron which has higherelasticity, thereby providing higher vibration damping and elasticdeformation to accommodate torque generated by the crankshaft. In otherembodiments, the gearbox housing 222 can be monolithically formed fromductile iron. A pair of lubricant filters are positioned on an outersurface of the third portion of the gearbox housing 222. The lubricantfilters can be fluidly coupled to a pump (not shown) configured to drawlubricant from lubricant reservoirs (not shown), so as to filter thelubricant before providing the lubricant to the gear set positionedwithin the internal volume defined by the gearbox housing 222. Suchlubricant reservoirs may be positioned at any suitable location on thechassis 250, or may be remotely mounted from the chassis and fluidlycoupled to the gearbox 220 via conduits.

In some embodiments, the gear set positioned within the internal volumedefined by the gearbox housing 222 includes a plurality of gears forproviding a mechanical linkage between the crankshaft and the generatorshaft that can provide a desired turn ratio, torque ratio, or reorientdirection of rotation from the crankshaft to the generator shaft. Forexample, the gear set can include a first gear shaft coupled to acrankshaft first end of the crankshaft, and a second gear shaft coupledto a generator shaft first end of the generator shaft.

In some embodiments, the first gear shaft is coupled to the crankshaftfirst end via a first coupling. In various embodiments, the firstcoupling can include a flex plate. A flywheel can be coupled to thecrankshaft first end and coupled to the flex plate. The first portion ofthe gearbox housing 222 can define an internal volume shaped and sizedto house the flywheel coupled to a crankshaft first end of thecrankshaft proximate to the gearbox 220.

The second gear shaft and the generator shaft can be coupled togethervia a second coupling which can include rubber coupling, a springcoupling, or a viscous coupling. The rubber coupling, spring coupling,or the viscous coupling can be structured to maintain operative couplingof the second gear shaft to the generator shaft under varying torqueconditions by allowing slight misalignment between the second gear shaftand the generator shaft. The second portion of the gearbox housing 222can also be sized and shaped to house the viscous coupling.

In some embodiments, a sidewall of the second portion of the gearboxhousing 222 is flared outwardly from the third portion to the second end225 of the gearbox housing 222. The flaring outwardly of the secondportion can, for example, allow a cross-section of the second portion atthe second end 225 to be significantly larger than a cross-section ofthe third portion. This allows the second end 225 of the gearbox housing222 to be physically coupled to the engine first end 211 over a largerarea, thereby increasing structural strength of the interface.Furthermore, the flaring can also allow space for the rubber, springcoupling, or viscous coupling positioned within the second portion tomove within an internal volume of the second portion, for example due toflexing, bending or otherwise elastic deformation of the gearbox housing222 in response to torque exerted by the crankshaft. Ribs or otherstrengthening features can also be defined on the first portion, thesecond portion and/or the third portion of the gearbox housing 222 toincrease the structural strength of the gearbox housing 222.

The gear set can be structured so that the crankshaft, at least aportion of the plurality of gears included in gear set and the generatorshaft are axially aligned along the longitudinal axis A_(L) of thegenerator set 100. In various embodiments, the gear set is structured tocause the generator shaft to rotate in the same direction as thecrankshaft. The structural coupling the gearbox housing 222 to each ofthe engine 210 and the generator 240 and/or the rotation of thecrankshaft 222 and the generator shaft in the same direction can causeeach of the engine 210, the gearbox 220 and the generator 240 to reactor otherwise torque react in the same direction in response to thetorque generated by the crankshaft.

The gears included in the gear set can include a first gear and a secondgear (collectively referred to herein as “the first pair of gears”)operably coupled to crankshaft and the generator shaft via the firstgear shaft and the second gear shaft, respectively. The first pair ofgears can be positioned to be axially aligned along the longitudinalaxis A_(L) of the genset 200 and can be structured to cause thegenerator shaft to rotate in the first direction as described before.

In some embodiments, the gear set also includes an auxiliary power gearoperably coupled the first pair of gears. The auxiliary power gear isstructured to be operably coupled to an auxiliary power source, forexample an exhaust gas recirculation turbines, or organic Rankine cycleturbine to provide auxiliary power to the gear set. This can increaseengine 210 efficiency or otherwise supplement the torque provided to thegenerator shaft to increase electrical output. In various embodiments,the auxiliary power gear can also be used to drive a main oil pumpfluidly coupled to the gearbox 220 to supply a lubricant therein tolubricate the gear set (e.g., from the lubricant reservoirs), filter thelubricant and/or exchange lubricant with an oil sump. An auxiliary oilpump (e.g., an electrical oil pump) can also be provided to provide apre-lubrication to the gear set before beginning of an operational runand/or provide backup oil supply in the event that the main oil pumpfails.

The gear set can also include an engine turning mechanism configured toturn the engine 210 over, i.e., rotate the crankshaft without startingthe engine 210, for example for maintenance or repair. For example, theengine turning mechanism may include an electric powered gear and isselectively coupleable to the gear set. Providing power to the electricpowered gear may cause the gear to couple to the gear set and rotate,thereby causing the gear set to rotate. This in turn rotates thecrankshaft so as to move a plurality of pistons positioned in aplurality of cylinders of the engine to displace therewithin.

In some embodiments, some or all of the gears included in the gear setinclude spur gears. In other embodiments, any other gear set can beincluded in the gearbox 220, such as a gear set including helical gears.

As described herein, the engine 210, the gearbox 220 and the alternator240 are coupled together and mounted as a structurally integral unit onthe chassis 250. The structural coupling allows spreading of the torqueload generated by the crankshaft through the gearbox housing 222 (or322) to the chassis 250, thereby reducing the load requirements of thechassis 250. Physically coupling the gearbox housing 222 to the engine210 and the generator 240 increases the structural strength at theinterface between the engine 210 and the generator 240 and reducing thetorque stress on the chassis 250. This may allow for optimized design ofthe chassis 250 for reduced torque load so as to allow strength andmaterial of the chassis 250 to be optimized and reduce cost.

Axial aligning of the crankshaft, the gearbox 220 and the generatorshaft as well as structural coupling of the gearbox 220 to the engine210 and the generator 240 allows the genset 200 to have smaller overalllength relative to other gensets which include a standalone gearbox oris not axially aligned. Axial alignment also enables the genset 200 tohave a lower chassis profile, and a smaller “moment arm” in theirmounting from the skid to apply reaction torque across, thereby allowingthe genset 200 of have a smaller height, increased stiffness, lessweight and have smaller space requirements. This enables the genset 200to fit more readily into enclosures and tight customer spaces andreduces handling and shipping costs. Furthermore, the gear set isstructured to allow rotation of the crankshaft and generator shaft inthe same direction which causes the engine 210, the gearbox 220 and thegenerator 240 to torque react in the same direction. This reducesoverall stress on the chassis 250 and the interface between the engine210 and the generator 240, as described with respect to the genset 200.

The gearbox 220 can increase the resonant frequencies to higher modeswhich are structurally less problematic. For example, FIGS. 3A-3C arefinite element analysis models of a genset that includes a gearboxsimilar to the gearbox of FIG. 2 according to an exemplaryimplementation. Various modes of vibration of the genset 200 are shownin FIGS. 3A-3C. For this genset, it was determined that the twistingnatural frequency of the generator set drops by about 40% when thefasteners coupling the gearbox to both the engine and generator areremoved. The vertical bending mode natural frequency also drops by about58%, thereby highlighting the increase in stiffness provided bystructurally coupling the gearbox to the engine and the generator.

In some embodiments, the gearbox 120/220 can also include a first flangerigidly coupling the first end 121/221 of gearbox housing 122/222 to theengine first end 111/211 and/or a second flange rigidly coupling thesecond end 125/225/to the generator second end 145/245. Variousembodiments of flanges, adaptors and coupling mechanisms for couplingthe gearbox 120/220 or any other gearbox described herein to the engineand/or the generator are described in European Patent Application No.15176912.2, filed Aug. 15, 2015 and entitled “Adaptor”, the entiredisclosure of which is incorporated herein by reference.

For example, FIG. 4 is a perspective view of a portion of a gearbox 420showing an end 425 of a gearbox housing 422 of the gearbox 420 rigidlycoupled to an alternator first end of a generator 440 via an adaptor460. The generator 440 can be substantially similar to the generator 140or 240 described herein, and therefore not described in further detailherein. In some embodiments, an opposite end of the gearbox housing 422can also be coupled to an engine first end of an engine (e.g., theengine 110 or 210) via the adaptor 460.

The adaptor 460 includes a first piece 462 a and a second piece 462 bremovably coupled to each other via fasteners (e.g., screws, nuts,bolts, etc.), as shown in FIG. 5. FIG. 6 is an exploded view of theadaptor 460. Each of the first piece 462 a and the second piece 462 binclude a first flange portion 468 a structured to interface with andcouple to the first end of the gearbox housing 422, and a second flangeportion 468 b structured to interface with and couple to the generatorfirst end of the generator 440. Throughholes 469 are defined througheach of the first flange portion 468 a and the second flange portion 468b. Fasteners such as screws, bolts, pins, etc., can be inserted throughthe throughholes into the gearbox housing 422 and the generator 440 torigidly couple the adaptor 460 thereto.

Each of the first piece 462 a and the second piece 462 b define aplurality of openings 464. The openings 464 allow users to access acoupling assembly 470 positioned within the adaptor 460 without removingthe adaptor 460, for example to perform maintenance operations.Furthermore, the first piece 462 a may be uncoupled from the secondpiece 462 b to facilitate replacement of the coupling assembly 470,without completely uncoupling the gearbox housing 422 from the generator440 (or the engine). A plurality of ribs 466 are also positioned on anouter surface of the adaptor 460. The ribs 466 provide additionalstructural strength while allowing reduction in weight of the adaptor460.

FIGS. 7-9 show a perspective view, an exploded view and a sidecross-section view, respectively of a coupling mechanism 470 which canbe used to operatively couple a second gear shaft of the gear box 420 orany other gearbox described herein to a generator shaft of the generator440 or any other generator described herein (e.g., the generator 140 or240). In some embodiments, the coupling mechanisms 470 can also be usedto couple a first gear shaft of the gearbox 420 to a crankshaft of anengine (e.g., the crankshaft 112/212 of the engine 110/210).

The coupling assembly 470 includes a flange 472 including a flangesegment 473 defining a plurality of flange throughholes 475 andstructured to be positioned on the generator first end of the generator440 within the adaptor 460. Fasteners 477 (e.g., screws or bolts) areinserted through the flange throughholes 475 to removably couple theflange segment 473 and thereby the flange 472 to the generator shaft ofthe generator 440 (or any other generator shaft of any generatordescribed herein) or a crankshaft of any engine described herein), forexample via a clutch plate (not shown).

A flexible coupling assembly 480 is positioned within the flange 472.The flexible coupling assembly 480 includes a first flexible coupler 482a and a second flexible coupler 482 b (collectively referred to hereinas “the flexible couplers 482”). The flexible couplers 482 includecircular elements and define a plurality of grooves 483 on an outercircumference thereof. The plurality of grooves 483 correspond to aplurality of ridges 474 defined on an inner surface of the flange 472 sothat the flexible couplers 482 can be immovably positioned within theflange 474. The flexible coupler s 482 can be formed from any suitableflexible material, for example rubber, silicone, polymers, etc.

Each of the flexible couplers 482 include a coupler flange segment 484defining a coupler channel therethrough. The coupler flange segment 484defines a plurality of coupler throughholes 485 structured to receivefasteners 479 for coupling a hollow sleeve 478 thereto. The sleeve 478defines a sleeve channel therethrough for receiving at least a portionof a first gear shaft or a second gear shaft, as described herein. Alocking assembly 476 is coupled to the sleeve 478 at a distal end of thesleeve relative to the flexible couplers 482 to removably couple thefirst generator shaft or the generator shaft to the sleeve 478.

In this manner, the first or second generator shaft is coupled to thesleeve 478 while the flange 472 is coupled to the generator shaft or thecrankshaft. Furthermore, the flange 472 and the sleeve 478 areoperatively coupled to each other via the flexible couplers 482. Duringoperation, the flexible couplers 482 may flex to allow slight rotationalmotion of the sleeve 478 relative to the flange 472, thereby allowingslight axial misalignment as well as torsional stresses due to torquegenerated by the crankshaft or the generator shaft.

In some embodiments, a first gear shaft and/or a second gear shaft of agearbox maybe coupled to a crankshaft or a generator shaft, respectivelyvia a torsionally elastic coupling. For example, FIG. 10 is a sidecross-section of a gearbox 520 according to an embodiment. The gearbox520 can be substantially similar to the gearbox 120, 220, 420 or anyother gearbox described herein. An elastic coupling 570 is positionedwithin a portion of an adaptor 560. The adaptor 560 is structured tocouple a first end 521 of the gearbox housing 522 to an engine first endof an engine (e.g., the engine first end 111/211 of the engine 110/210).In some embodiments, the adaptor 560 can be substantially similar to theadaptor 460 described in detail herein.

FIG. 11 is a perspective view of the elastic coupling 570 according toan embodiment. In some embodiments, the elastic coupling 570 can includea Geislinger coupling. The elastic coupling 570 includes a circularmember which includes a first series of throughholes 573 defined on anouter portion 572 thereof. The first series of throughholes 573 areconfigured to receive fasteners (e.g., screws, bolts etc.) for removablycoupling the elastic coupling 570 to a crankshaft or a generator shaft.Furthermore, the elastic coupling 570 includes an inner portion 574defining a second series of throughholes 575. The second series ofthroughholes 575 are also structured to receive fasteners to couple afirst gear shaft 532 or the second gear shaft to the elastic coupling570.

The outer portion 572 is structurally coupled to the inner portion viahigh-damping members 576 (e.g., high-damping steel springs) such thatthe elastic coupling 570 is torsionally elastic and provideshydrodynamic damping. The elastic coupling 570 provides highreliability, long service life and low life-cycle costs. In variousembodiments, an interface sleeve 592 may be coupled to the innerportion. The interface sleeve 592 defines a channel 593 for providingoil, for example gear oil or engine oil, to the inner portion of theelastic coupling 570.

FIGS. 12 and 13 are perspective views of an embodiment of a skid frameor chassis 650 which can be used for rigidly mounting an engine, agearbox and a generator included in a genset assembly (e.g., the gensetassembly 100, 200, or any other genset assembly described herein)thereon. The skid frame 650 includes outer beams 654. A first rigidcross-beam 651 is positioned orthogonally between the beams 654 andrigidly coupled thereto proximal to a first end of the skid frame 650. Asecond rigid cross-beam 652 is positioned orthogonally between the beams654 and rigidly coupled thereto proximal to a second end of the skidframe 650. Furthermore, a third rigid cross-beam is positionedorthogonally between the beams 654 and rigidly coupled thereto proximalto a center of the skid frame 650. The first cross-beam 651, the secondcross-beam 652, and the third cross-beam 659 may be structured toprovide structural strength, for example to resist torsion or bending atvarious locations of the skid frame 650. In some embodiments, one ormore of the first cross-beam 651, the second cross-beam 652, and thethird cross-beam 659 may include round lift tubes for lifting thechassis 650, and/or coupling the beams 654 to each other.

A first cross member 652 is positioned orthogonally between the beams654 and rigidly coupled thereto proximal to a first end of the skidframe 650. The first end corresponds to a portion of the skid frame onwhich an engine (e.g., the engine 110, 210 or any other engine describedherein) is mounted. A first plate 653 is also positioned proximal to thefirst end. The first cross-beam 652 may provide structural strengthwhile the first plate 653 may be used for mounting genset accessoriesand to provide structural strength, for example by resisting twistingand bending at the corresponding end of the chassis.

A second rigid cross-beam 659 is positioned proximal to a center of theskid frame 650. The second cross-beam 659 is structured to providestructural strength of torsion resistance to the skid frame 650 proximalto a location of the genset assembly wherein the gearbox couples to theengine. A series of X beams 655 are positioned proximate to the secondcross-beam corresponding to a portion of the skid frame 650 where thegearbox is positioned. The X beams 655 may include a sub-assemblycoupled to chassis 650, or alternately integrated with the chassis, forproviding additional structural strength of the skid frame 650 tocounter the high torque forces acting on the gearbox.

A gearbox housing of the gearbox positioned on the skid frame 650 (e.g.,the gearbox 120, 220, 420, 520, or any other gearbox defined herein) maybe coupled to the chassis 650 via an interface. For example, the gearboxhousing can include feet including apertures for coupling the gearboxhousing to the skid frame 650 via fasteners (e.g., screws, bolts,rivets, pins, etc.). In some embodiments, shock absorbers such assprings, rubber pads, foam pads, vibracons, hydraulic dampers or anyother shock absorbing assembly can positioned between the gearboxhousing and the skid frame 150. The skid frame 650 also includes rails658 for mounting the gearbox thereon. The gearbox can be moved along therails so as to accommodate different length engines or generators on theskid frame 650.

In some embodiments, a gearbox oil tank (not shown) may be remotelymounted from the chassis 650 and be fluidly coupled to the gearbox viaconduits. In other embodiments, the gearbox oil tank maybe mounted atany suitable location on the chassis 650 A pair of second beams 656 ispositioned vertically offset from the outer beams 654 so that the pairof second beams 656 are higher than the outer beams 654. The pair ofsecond beams 656 are structured to provide a raised structure formounting the generator on the skid frame 650 (i.e., providing agenerator frame), for example to allow axial alignment of a generatorshaft of the generator with a second gear shaft of the gearbox. In someembodiments, the vertically offset pair of second vertical beams 656 maybe excluded.

FIG. 14 is a schematic flow diagram of an example method 700 formechanically coupling an engine including a crankshaft (e.g., the engine110/210 including the crankshaft 112/212) to a generator including agenerator shaft (e.g., the generator 140/240 including the generatorshaft 144/244) using a gearbox (e.g., the gear box 120, and/or 220) asdescribed herein. The method 700 includes providing a gearbox housinghaving a first end, a second end and a plurality of gears, a first gearshaft and a second gear shaft at 702. For example, the gearbox caninclude the gearbox 120, 220, or any other gearbox described herein. Thegearbox 120/220 include the first end 121/221, the second end 125/225,and a plurality of gears. The plurality of gears also include a firstgear shaft 132/232 and a second gear shaft 134/234 coupled to at least aportion of the plurality of gears.

The first end of the gearbox housing is coupled to an engine first endof the engine at 704. For example, the first end 121/221 of the gearboxhousing 122/222 is coupled using fasteners or any suitable couplingmeans as described herein to the engine first end 111/211 of the engine110/210. The first gear shaft is coupled to a crankshaft first end ofthe crankshaft at 706. For example, a flywheel can be coupled to thecrankshaft first end of the crankshaft 112/212 of the engine 110/210 andthe first gear shaft 132/232 is operatively coupled to the flywheel viaa first coupling 133/233 such as a flex plate.

The second end of the gearbox housing is coupled to a generator firstend of the generator at 708. For example, the second end 125/225 of thegearbox housing 122/222 is coupled to the generator first end 145/245 ofthe generator 140/240 using fasteners or any suitable couplingcomponents as described herein. The second gear shaft is coupled to agenerator shaft first end of the generator at 710. For example, thesecond gear shaft 134/234 is coupled to the generator shaft 144/244 viaa second coupling 135/235, for example a rubber coupling or viscouscoupling, as described herein.

Each of the engine, the gearbox and the generator are positioned on achassis and rigidly coupled thereto at 712. For example, the engine110/210, the gearbox 120/220 and the generator 140/240 are positioned onthe chassis 150/250. In some embodiments, the engine, the gearbox andthe generator are first positioned on the chassis before being coupledto each other. The physical coupling of the engine, the gearbox housingand the generator increases the structural strength of the gensetassembly as described herein. Furthermore, the gearbox (e.g., thegearbox 120 and/or 220) is positioned so that the crankshaft (e.g., thecrankshaft 112/212), at least a portion of the plurality of gears andthe generator shaft (e.g., the generator shaft 144/244) are axiallyaligned. The gearbox (e.g., the gearbox 120 and/or 220) can bestructured to cause the generator shaft to rotate in the same directionas the crankshaft. The rotation in the same direction and structuralcoupling of the engine, the gearbox and the generator causes the engine,the gearbox and the generator to react in the same direction in responseto a torque generated by the crankshaft.

FIG. 15 shows a schematic illustration of a generator set 800 accordingto an embodiment. The generator set 800 may include a large generatorset, for example having a power rating of greater than 500 kW. Thegenerator set 100 includes the engine 110 including the crankshaft 112,a gearbox 820, the generator 140 including the generator shaft 144, andthe skid frame or chassis 150. The gearbox 820 is positioned between theengine 110 and the generator 140 and operatively couples the crankshaft112 to the generator shaft 144, thereby allowing mechanical energy to betransmitted from the crankshaft 112 to the generator shaft 144 forproducing electrical energy. The crankshaft 112 and the generator shaft144 are axially aligned along a longitudinal axis A_(L) of the generatorset 100 via the gearbox 820. In some embodiments, the crankshaft 112 andthe generator shaft 114 may be vertically aligned.

The gearbox 820 includes a gearbox housing 822 and a gear set 830positioned within an internal volume defined by the gearbox housing 822.The gear set 830 includes a first gear shaft 832 coupled to a crankshaftfirst end of the crankshaft 112 via a first coupling 833 (e.g., thefirst coupling 133), and a second gear shaft 834 coupled to a generatorshaft first end of the generator shaft 144 via a second coupling 835(e.g., the second coupling 135). The gear set 830 may include simple 2gears, sun gears, planetary gears, epicyclic gears or any other suitablegear assembly.

The gearbox housing 822 includes a first end 821 coupled to an enginefirst end 111 of the engine 110. Furthermore, the gearbox housing 822includes a second end 825 coupled to a generator first end 145 of thegenerator 140. The structural coupling of the engine 810, the gearboxhousing 822 and the generator 140 provides enhanced mechanical stiffnessand strength to the genset 800. Because of the structural coupling, theengine 110, the gearbox housing 822 and the generator 140 may form anintegrated torque bearing structure or a “torque tube” for transmissionof torque load between the coupled elements of the engine 110, thegearbox 820, and the generator 140.

The engine 110 and the generator 140 are positioned on and rigidlycoupled to the skid frame or chassis 150, while the gearbox housing 822is rigidly coupled to the engine first end 111 and the generator firstend 145 as described herein. The rigid coupling of the gearbox housing822 to the engine 110 and the generator 140 which are rigidly coupled tothe chassis 150 and to each other further adds to the structuralstrength of the torque tube structure formed thereby.

Expanding further, the engine 110 and the generator 140 may havesignificant mass. Generally, a gearbox is positioned on the chassis 150but not structurally coupled to the engine 110 and the generator 140such that the chassis 150 is the only structural member that couples theengine 110 and the generator 140. FIG. 15A shows a side cross-section ofthe chassis 150 having a neutral axis. The stiffness of a gearboxpositioned on the chassis 150 between the engine 110 and the generator140 but not coupled thereto, highly corresponds to an area moment ofinertia of the chassis 150.

In contrast, the gearbox 820 and the other gearboxes described hereinare rigidly coupled via stiff connectors (e.g., fasteners such as bolts,screws, nuts, rivets, etc.) to engine 110 and the generator 140. FIG.15B shows the side cross-section of the generator set 800 with thegearbox 820 stiffly and rigidly coupled to the engine 110 and thegenerator 120. As shown in FIG. 15B, the structural coupling of thegearbox 820 (or any other gearbox described herein) shifts the neutralaxis of the generator set 800 towards a more central location of thegenerator set 800 which greatly increases the stiffness of the generatorset 800.

FIG. 16 shows a schematic illustration of a generator set 900 accordingto an embodiment. The genset 900 may include a large genset, for examplehaving a power rating of greater than 500 kW. The generator set 900includes the engine 110 including the crankshaft 112, a gearbox 920, thegenerator 140 including the generator shaft 144, and the skid frame orchassis 150. The gearbox 920 is positioned between the engine 110 andthe generator 140 and operatively couples crankshaft 112 to thegenerator shaft 144, thereby allowing mechanical energy to betransmitted from the crankshaft 112 to the generator shaft 144 forproducing electrical energy. The crankshaft 112 and the generator shaft144 are axially aligned along a longitudinal axis A_(L) of the generatorset 100 via the gearbox 920.

The gearbox 920 includes a gearbox housing 922 and a gear set 930positioned within an internal volume defined by the gearbox housing 922.The gear set 930 includes a first gear shaft 932 coupled to a crankshaftfirst end of the crankshaft 112 via a first coupling 933 (e.g., thefirst coupling 133), and a second gear shaft 934 coupled to a generatorshaft first end of the generator shaft 144 via a second coupling 935(e.g., the second coupling 135). The gear set 930 may include simple 2gears, sun gears, planetary gears, epicyclic gears or any other suitablegear assembly.

The gearbox housing 922 includes a housing first portion 922 apositioned on and coupled to the chassis 150. The gearbox housing 822also includes a housing second portion 922 b having a second portionfirst end 921 b coupled to the engine first end 111 of the engine 110but not to the chassis 150. Furthermore, the gearbox housing 222 alsoincludes a housing third portion 922 c having a second portion first end925 c coupled to the generator first end 145 but not to the chassis 150.

The engine 110, the generator 140 and the housing first portion 922 aare positioned on and rigidly coupled to the skid frame or chassis 150.Furthermore, the housing second portion 922 b and the housing thirdportion 922 c form stiff and rigid coupling with the engine 110 and thegenerator 140, respectively as described herein. In this manner, therigid coupling of the gearbox housing 922 to the engine 110 and thegenerator 140 which are rigidly coupled to the chassis 150 and to eachother further adds to the structural strength of the torque tubestructure formed thereby. The gearbox 922 may allow for optimized designof the chassis 150 for reduced torque load so as to allow strength andmaterial of the chassis 150 to be optimized and reduce cost.

FIG. 17 shows a schematic illustration of a generator set 1000 accordingto an embodiment. The genset 1000 may include a large generator set, forexample having a power rating of greater than 500 kW. The generator set1000 includes the engine 110 including the crankshaft 112, a gearbox1020, the generator 140 including the generator shaft 144, and the skidframe or chassis 150. The gearbox 920 is positioned between the engine110 and the generator 140 and operatively couples crankshaft 112 to thegenerator shaft 144, thereby allowing mechanical energy to betransmitted from the crankshaft 112 to the generator shaft 144 forproducing electrical energy.

The crankshaft 112 is positioned along a first axial axis A_(L1) and thegenerator shaft 144 is positioned along a second axial axis A_(L2) whichis axially offset from the from first axial axis A_(L1). The gearbox1020 includes a gearbox housing 1022 and a gear set 1030 positionedwithin an internal volume defined by the gearbox housing 1022. The gearset 1030 includes a first gear 1030 a having a first gear shaft 1032coupled to a crankshaft first end of the crankshaft 112 via a firstcoupling 1033 (e.g., the first coupling 133). The first gear shaft 1032is axially aligned with the first axial axis A_(L1) of the crankshaft112.

The gear set 1030 also includes a second gear 1030 b having a secondgear shaft 1034 coupled to a generator shaft first end of the generatorshaft 144 via a second coupling 1035 (e.g., the second coupling 135).The second gear shaft 1034 is axially aligned with the second axial axisA_(L2) of the crankshaft 112, such that the crankshaft 112 and thegenerator shaft 144 are operatively coupled to each other while beingaxially offset from each other. The gear set 1030 may include simple 2gears, sun gears, planetary gears, epicyclic gears or any other suitablegear assembly.

The gear set 1030 may be configured to convert a rotational motion ofthe crankshaft 112 along a first rotational direction about the firstaxial axis A_(L1) as shown by the arrow A (e.g., a counter clock-wiserotation) to a rotational motion of the generator shaft 144 about asecond rotational direction opposite the first rotational direction asshown by the arrow B (e.g., a clockwise direction). In some embodiments,the gear set 1030 may be configured such that the first rotationaldirection and the second rotational direction are in the same rotationaldirection (e.g., clockwise or counter clockwise direction).

The gearbox housing 1022 includes a housing first portion 1022 apositioned on and coupled to the chassis 150. The gearbox housing 1022also includes a housing second portion 1022 b having a second portionfirst end 1021 b coupled to the engine first end 111 of the engine 110but not to the chassis 150. Furthermore, the gearbox housing 1022 alsoincludes a housing third portion 1022 c having a second portion firstend 1025 c coupled to the generator first end 145 but not to the chassis150.

The engine 110 and the housing first portion 1022 a are positioned onand rigidly coupled to the skid frame or chassis 150. While FIG. 17shows the generator 140 detached from the chassis 150, in someembodiments, the generator 140 may also be coupled to the chassis 150.For example, a generator frame 146 may be positioned on and rigidlycoupled to the chassis 150. The generator 140 may be positioned on thegenerator frame 146 (e.g., a raised platform) and rigidly coupledthereto so as to rigidly couple the generator 140 to the chassis 150.Furthermore, the housing second portion 1022 b and the housing thirdportion 1022 c form stiff and rigid coupling with the engine 110 and thegenerator 140, respectively as described herein. The gearbox 1022 mayallow for optimized design of the chassis 150 for reduced torque load soas to allow strength and material of the chassis 150 to be optimized andreduce cost.

FIG. 18 is an isometric view of a genset 1100, for example having apower rating of greater than 500 kW. The generator set 1100 includes anengine 1110 including a crankshaft (not shown), a gearbox 1010, agenerator 1140 including a generator shaft (not shown), and a skid frameor chassis 1150. The engine 1110 and the generator 1140 may besubstantially similar to the engine 110/210, and the generator 140/240,respectively or any other engine or generator described herein. The skidframe 1150 may be substantially similar to the skid frame 650 shown inFIGS. 12 and 13, or any other skid frame described herein.

The gearbox 1120 is positioned between the engine 1110 and the generator1140 and operatively couples the crankshaft to the generator shaft,thereby allowing mechanical energy to be transmitted from the crankshaftto the generator shaft for producing electrical energy. The engine 1110and the gear box 1120 are positioned on and rigidly coupled to the skidframe or chassis 1150. The generator 1140 is positioned on the generatorframe 1146 (e.g., a raised platform) and rigidly coupled thereto so asto rigidly couple the generator 1140 to the skid frame 1150.Furthermore, a housing of the gearbox 1120 is rigidly coupled to each ofthe engine 1110 and the generator 1140. The gearbox 1120 may allow foroptimized design of the chassis 1150 for reduced torque load so as toallow strength and material of the chassis 1150 to be optimized andreduce cost.

As used herein, the singular forms “a”, “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, the term “a member” is intended to mean a single member or acombination of members, “a material” is intended to mean one or morematerials, or a combination thereof.

As used herein, the terms “about” and “approximately” generally meanplus or minus 10% of the stated value. For example, about 0.5 wouldinclude 0.45 and 0.55, about 10 would include 9 to 11, about 1000 wouldinclude 900 to 1100.

The terms “coupled,” and the like as used herein mean the joining of twomembers directly or indirectly to one another. Such joining may bestationary (e.g., permanent) or moveable (e.g., removable orreleasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

It is important to note that the construction and arrangement of thevarious exemplary embodiments are illustrative only. Although only a fewembodiments have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Othersubstitutions, modifications, changes and omissions may also be made inthe design, operating conditions and arrangement of the variousexemplary embodiments without departing from the scope of the presentinvention.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular implementations of particularinventions. Certain features described in this specification in thecontext of separate implementations can also be implemented incombination in a single implementation. Conversely, various featuresdescribed in the context of a single implementation can also beimplemented in multiple implementations separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

What is claimed is:
 1. A generator set, comprising: an engine includinga crankshaft rotatable in a first direction about a longitudinal axis ofthe generator set; a generator including a generator shaft; a gearboxpositioned between the engine and the generator and coupling thecrankshaft to the generator shaft, the gear box including: a gearboxhousing having a first end and a second end, the first end structured tocouple to an engine first end of the engine and the second endstructured to couple to a generator first end of the generator, a firstflange rigidly coupling the first end of the gearbox housing to theengine first end, a second flange rigidly coupling the second end of thegearbox housing to the generator first end, and a gear set including aplurality of gears, a first gear shaft coupled to a crankshaft first endof the crankshaft, and a second gear shaft coupled to a generator shaftfirst end of the generator shaft; and a skid frame, each of the engine,the gearbox and the generator positioned on and rigidly coupled to theskid frame, wherein the crankshaft, at least a portion of the pluralityof gears, and the generator shaft are axially aligned along thelongitudinal axis of the generator set, and wherein the gearboxinterfaces with the engine and the generator to form a rigid torque tubestructure.
 2. The generator set of claim 1, wherein the gearbox causesthe generator shaft to also rotate in the first direction.
 3. Thegenerator set of claim 1, wherein the gearbox causes the generator shaftto rotate in a second direction opposite the first direction.
 4. Thegenerator set of claim 2, wherein the gearbox causes each of the engine,the gearbox and the generator to react in the same direction in responseto a torque generated by the crankshaft.
 5. The generator set of claim1, wherein the first gear shaft and the crankshaft first end are coupledtogether via a flex plate.
 6. The generator set of claim 5, furthercomprising: a flywheel coupled to the crankshaft first end, the flywheelcoupled to the flex plate.
 7. The generator set of claim 6, wherein theflywheel is positioned within an internal volume defined by the gearboxhousing.
 8. The generator set of claim 1, wherein the second gear shaftand the generator shaft are coupled together via at least one of arubber coupling or a viscous coupling.
 9. The generator set of claim 1,wherein the gear set comprises: a first pair of gears operably coupledto the crankshaft and the generator shaft via the first gear shaft andthe second gear shaft, the first pair of gears axially aligned along thelongitudinal axis of the generator set.
 10. The generator set of claim9, wherein the gear set further comprises: a second pair of gearsoperably coupled to the first pair of gears, the second pair of gearsaxially offset from the longitudinal axis of the generator set.
 11. Thegenerator set of claim 1, wherein at least one of the first flange orthe second flange includes an adaptor, the adaptor including a firstpiece and a second piece removably coupled to each other so as to allowaccess to a coupling positioned therewithin.
 12. The generator set ofclaim 1, wherein the generator, the gear box and the engine mounted onthe skid frame are structured to be securely positioned within anenclosure.
 13. A gearbox for coupling a crankshaft of an engine to agenerator shaft of a generator, comprising: a gearbox housing having afirst end and a second end, the first end structured to couple to anengine first end of the engine and the second end structured to coupleto a generator first end of the generator, the gear box housingstructured to be positioned on and rigidly coupled to a skid frame; anda gear set including a plurality of gears, a first gear shaft and asecond gear shaft, the first gear shaft structured to couple to a crankshaft first end of the crankshaft, and a second gear shaft structured tocouple to a generator shaft first end of the generator shaft such thatthe crankshaft, at least a portion of the plurality of gears, and thegenerator shaft are axially aligned when the gearbox is coupled to theengine and generator.
 14. The gearbox of claim 13, wherein the gearboxis structured to allow rotation of the crankshaft and the generatorshaft in the same direction.
 15. The gearbox of claim 13, whereincoupling of the gearbox housing to the engine and the generator causesthe engine, the gearbox and the generator to form a torque tubestructure, the torque tube structure reacting in the same direction inresponse to a torque generated by the crankshaft.
 16. The gearbox ofclaim 13, further comprising: a flex plate positioned on the first gearshaft, the flex plate structured to couple to a flywheel positioned onthe crankshaft first end.
 17. The gear box of claim 16, wherein thegearbox housing defines an internal volume, the flywheel positionablewithin the internal volume.
 18. The gear box of claim 13, wherein thegear set includes: a first pair of gears structured to couple to thecrankshaft and the generator shaft via the first gear shaft and thesecond gear shaft, the first pair of gears oriented to axially alignwith a longitudinal axis of each of the crankshaft and the generatorshaft.
 19. The gear box of claim 18, wherein the gear set furtherincludes: a second pair of gears operably coupled to the first pair ofgears, the second pair of gears axially offset from the first pair ofgears.
 20. The gear box of claim 13, further comprising: a first flangerigidly coupling the first end of the gearbox housing to the enginefirst end, and a second flange rigidly coupling the second end of thegearbox housing to the generator first end.
 21. The gear box of claim13, wherein at least one of the first flange or the second flangeincludes an adaptor, the adaptor including a first piece and a secondpiece removably coupled to each other, at least one of the first pieceor the second piece removable to allow access to a coupling positionedtherewithin.
 22. The gearbox of claim 21, wherein the adaptor includes aplurality of openings defined in the first piece and the second piece,the plurality of openings structured to allow access to the couplingwithout uncoupling the first piece from the second piece.
 23. A methodof coupling a crankshaft of an engine to a generator shaft of agenerator, comprising: providing a gear box, the gearbox including agearbox housing having a first end and a second end, and a gear setincluding a plurality of gears, a first gear shaft and a second gearshaft; coupling the first end of the gearbox housing to an engine firstend of the engine; coupling the first gear shaft to a crankshaft firstend of the crankshaft, at least a portion of the plurality of gearsaxially aligned with the crankshaft; coupling the second end of thegearbox housing to a generator first end of the generator; coupling thesecond gear shaft to a generator shaft; and positioning each of theengine, the generator and the gearbox on a skid frame, the engine, thegearbox and the generator rigidly coupled to the skid frame, wherein thecoupling of the first gear shaft to the crankshaft and the second gearshaft to the generator shaft causes the crankshaft, at least a portionof the plurality of gears and the crankshaft to be axially aligned sothat that the engine, the gearbox and the generator form a rigid torquetube structure.
 24. The method of claim 23, wherein coupling of thefirst gear shaft to the crankshaft first end and the second gear shaftto the generator set first end allows the crankshaft and the generatorshaft to rotate in the same direction.
 25. The method of claim 23,wherein the coupling of the first end of the gearbox housing to theengine first end and the coupling of the second end of the gearboxhousing to the generator first end causes each of the engine, thegearbox and the generator to react in the same direction in response toa torque generated by the crankshaft.
 26. A generator set, comprising:an engine including a crankshaft rotatable in a first direction about alongitudinal axis of the generator set; a generator including agenerator shaft; a gearbox positioned between the engine and thegenerator and coupling the crankshaft to the generator shaft, thegearbox comprising: a gearbox housing having a first end and a secondend, a first flange rigidly coupling the first end of the gearboxhousing to an engine first end of the engine, a second flange rigidlycoupling the second end of the gearbox housing to a generator first endof the generator, and a gear set including a plurality of gears, a firstgear shaft coupled to a crankshaft first end of the crankshaft, and asecond gear shaft coupled to a generator shaft first end of thegenerator shaft; and a skid frame, each of the engine and the generatorpositioned on and rigidly coupled to the skid frame.
 27. The generatorset of claim 26, wherein the gearbox is configured to operatively couplethe crankshaft to the generator shaft such the crankshaft and generatorshaft are horizontally aligned, vertically aligned, or horizontallyoffset from each other.
 28. The generator set of claim 26, wherein thegearbox is configured to cause the crankshaft and the generator shaft tobe axially aligned, and wherein the gearbox includes planetary gears.